Segment Disclosures - Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 5,820,808	$ 5,777,141
Finance Lease, Right-of-Use Asset	15,419	15,772
Contract land deposit reserve	(46,008)	(52,205)
Home Building Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	5,405,619	5,214,516
Cash and cash equivalents	2,753,123	2,714,720
Operating lease right-of-use assets	50,770	53,110
Mortgage Banking
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	415,189	562,625
Cash and cash equivalents	21,061	63,547
Operating lease right-of-use assets	12,087	12,439
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,733,097	2,770,522
Operating Segments | Home Building Segment | Mid Atlantic
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,171,850	1,140,910
Operating Segments | Home Building Segment | North East
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	228,644	202,591
Operating Segments | Home Building Segment | Mid East
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	403,637	377,448
Operating Segments | Home Building Segment | South East
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	521,124	494,295
Operating Segments | Mortgage Banking
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	407,842	555,278
Corporate and Reconciling Items
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	3,087,711	3,006,619
Cash and cash equivalents	2,753,123	2,714,720
Deferred taxes	134,930	132,980
Intangible assets and goodwill	49,640	49,678
Operating lease right-of-use assets	50,770	53,110
Finance Lease, Right-of-Use Asset	15,419	15,772
Contract land deposit reserve	(46,008)	(52,205)
Consolidation adjustments and other	$ 129,837	$ 92,564